Deafness, dystonia, and cerebral hypomyelination (DDCH; MIM#300475) is an X‐linked severe neurological disorder caused by hemizygous mutations of BCAP31. This condition was first defined in detail by Cacciagli et al.(2013) based on the observation of 11 affected male patients from unrelated three families through an attempt to identify mutations causing X‐linked intellectual disability by using next‐generation sequencing (Cacciagli et al., 2013). Here, BCAP31 is linked to Dystonia.